Thermology: History, What It Studies And Basic Concepts

The thermology is a branch of science related to physics that deals with the study of the effects of heat and temperature on matter . For example, analyzes the behavior of cells when exposed to different temperatures, since their movements can increase or decrease depending on the heat levels

It is also used in medicine, through the use of thermography. This uses the use of special cameras that detect infrared radiation. Any body that emits radiation and that exceeds zero temperature can be observed through thermography, regardless of whether or not there is a light source in the environment.

Thermography is known for its non-invasive nature, since it does not require the use of radiation to be applied in examinations of people. Among some of the diagnoses that can be made are: breast cancer, diabetes, arthritis, metabolic disorders, headaches or back pain problems or disorders in the nervous system .

What does thermology study? (Object of study)

Thermology focuses on the study of heat and everything that it can cause to matter through different phases or processes. Heat is capable of modifying the states of matter based on the behavior of cells. Different temperatures or different intensities of heat can generate different reactions in bodies at the cellular level.

Among some of the elements of study of thermology is heat and temperature, which appear as the main concepts. Thermology uses the use of measuring instruments such as the thermometer, in order to determine the level of heat that an object has.

Thermology emphasizes the study of matter and the extent to which heat is capable of modifying it. Each body has particular characteristics, so heat does not act in the same way in all cases.

Thermology can study, for example, the way in which heat acts on a liquid and at what moment it is able to freeze or boil, thus going from a liquid to a solid or a gaseous state.

History of thermology

First applications

Since ancient times, human beings have been interested in the studies of heat. For example, Greek physicists already formulated ideas about it and Aristotle argued that heat is a quality inherent to matter. Other scholars related heat to the parts of the body that move the most. 

In the 400th century BC. C., many physicists applied mud baths on the body of their patients while they observed how the different areas were drying. This way they identified different levels of temperature distributed in the human body. This technique could be considered one of the precursors of the thermography.

That is, for the time, the heat was already associated with health problems. In fact, Eminences such as Hippocrates argued that in any area of ​​the body where there was excess heat, a disease was hidden. 

Technical advances during the Scientific Revolution

During the 16th century, the first attempts to measure heat arose. Among these is the development of the thermoscope by Galileo Galilei (1564-1642), who noted that the density of liquids can change depending on the temperature. 

The instrument consisted of a glass cylinder whose interior was filled with alcohol and water. Inside the cylinder were several counterweighted glass spheres containing colored liquids. At the same time, Santorio Santorio (1561-1636), using Galileo’s references, invented the clinical thermometer to be able to make measurements on his patients. 

Thanks to the advances in the techniques for the use of glass, in 1641, Ferdinand II de Medici, Duke of Tuscany, developed the alcohol bulb thermometer, the main reference of those used today. 

During the 17th century, Robert Boyle (1627-1691), of English origin, established the first two laws related to the concept of temperature. He also contributed to the discovery of the “law of equilibrium”, in which it is expressed that all bodies that are exposed to the same conditions of heat or cold are capable of reaching the same temperature.

Heat scales are born

In 1714, Daniel Gabriel Fahrenheit managed to develop the first mercury thermometer and create the well-known “Fahrenheit” temperature scale, which is still in force in many countries such as the United States. Fahrenheit was able to measure the variation of the boiling point of water under different pressure conditions of the environment and observed that each liquid substance has a different boiling point .

At that time, Anders Celsius (1701-1744) designated as reference points for his thermometer the melting and boiling point of water when they are at sea level. The name of the Celsius scale was called the “centigrade scale.” Later it was renamed with the name of its inventor as “degrees Celsius”. 

Another recognized scale is the degree Kelvin or absolute scale, which was developed by the mathematical physicist Lord William Thomson Kelvin (1824-1907). His study was based on the movement of molecules.

For this reason, he designated the value of “zero temperature” as the point at which molecular motion stops. Hence it is designated that any body that has a temperature greater than or equal to “absolute zero” is capable of emitting thermal energy or heat.

First uses in medicine

By the 19th century the measurement of temperature began to be integrated in relation to the detection of diseases. The French doctor and bacteriologist, Alfred François Donné (1801-1878), conducted a trial with his applied research in more than 1800 patients affected with fever, using an axillary thermometer designed by him.

Later, Carl Reinhold August Wunderlich (1815-1877), a German physicist and professor, demonstrated that fever is a symptom and not a disease, for which he defined a normal range of body temperature between 36.3 and 37.5 ºC. However, the use of the thermometer became widespread later, when Thomas Clifford Allbut designed the 12 cm portable thermometer in 1866. 

Principles of thermography

In the 20th century, scientists began to analyze the infrared spectrum through photography. In fact, during World War II many advances were made regarding the development of infrared sensors, which were very useful for armies.

In 1960, multiple investigations dedicated to the use of thermal images increased the knowledge of science. In 1972 it was announced that thermography, as it began to be called at the time, was being used in areas of medicine to study some parts of the body such as women’s breasts. Starting in the 1980s, many physicists and technicians continued to develop the equipment and the medical application was on the rise.

At present, thermography is applied in different branches such as neurology, vascular medicine, sports medicine and many more fields. This is how the development of thermology has made its advances over time, becoming, together with thermography, one of the most relevant fields in medical studies of the human body.

Related concepts


It refers toto measure the degree of agitation of the particles of a body. This comes from the fact that the temperature of a body is given by the speed with which its molecules move.

Thermometric scales

They are the scales that are used to measure temperature using some fixed reference points. The three best known thermometric scales are Celsius, Fahrenheit, and Kelvin.


It is a form of thermal energy that can be transferred between bodies that have different temperatures. Heat usually transits from a higher temperature body to lower temperature bodies, until a thermal equilibrium is achieved. There are three known forms of heat transmission: by conduction, convection, and irradiation.

Thermal expansion

It is generated when a body receives or generates large amounts of heat. This effect can generate changes in the physical state in a body.


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